In Situ Hydrothermal Synthesis of Ni1-xMnxWO4 Nanoheterostructure for Enhanced Photodegradation of Methyl Orange.

The monoclinic nanocrystalline Ni1-xMnxWO4 heterostructure has been successfully synthesized by the hydrothermal technique for achieving better sensitive and photocatalytic performances. Different characterization techniques such as X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), ultraviolet-visible (UV-Vis), and photoluminescence (PL) spectroscopy have been employed to investigate their structural, microstructural, and optical properties. Mn-ion incorporation in the NiWO4 lattice reduces the particle size of the sample compared with the pure undoped NiWO4 sample, which has been confirmed from the transmission electron microscope image. The Tauc plot of the Ni1-xMnxWO4 sample exhibits a significant decrease in bandgap energy compared with the pure undoped NiWO4 sample due to the quantum confinement effect. Finally, the material was explored as a photocatalyst for the degradation of methyl orange (MO) dye from wastewater under visible light irradiation. Various reaction parameters such as pH, catalyst dose, reaction time, and kinetics of the photodegradation were studied using the batch method. The results showed that the Ni1-xMnxWO4 is highly efficient (94.51%) compared with undoped NiWO4 (65.45%). The rate of photodegradation by Ni1-xMnxWO4 (0.067) was found to be 1.06 times higher than the undoped NiWO4 (0.062).

Zinc Vanadate (Zn3V2O8) Immobilized Multiwall Carbon Nanotube (MWCNT) Heterojunction as an Efficient Photocatalyst for Visible Light Driven Hydrogen Production.

Z-scheme photocatalytic reaction is considered an effective strategy to promote the photogenerated electron-hole separation for significantly improving the efficiency of photocatalytic hydrogen precipitation from splitting water. In this study, a heterojunction nanocomposite material based on Zn3V2O8 (ZV) with MWCNT was prepared by a hydrothermal process. The photocatalysts were characterized by X-ray diffraction, scanning electron microscopy (SEM), Fourier transform infrared (FTIR), UV-visible absorption spectroscopy, and transmission electron microscopy (TEM) to understand crystal structure, morphology, and optical properties. The efficiency of the samples was evaluated for the photocatalytic H2 production under visible solar radiation using water glycerol as a sacrificial reagent. The obtained results suggest that, between ZV and ZV@MWCNT, the latter shows higher efficiency for H2 production. The maximum H2 production efficiency was found to be 26.87 µmol g-1 h-1 for ZV and 99.55 µmol g-1 h-1 for ZV@MWCNT. The synergistic effect of MWCNT to ZV resulted in improving the efficiency of charges and light-absorbing capacity, resulting in enhanced H2 production in the heterojunction nanocomposite material. The nanocomposite was stable and highly efficient for H2 production of six or more cycles. Based on the outcomes of this study, it can be observed that forming the heterojunction of individual nano systems could result in more efficient material for H2 production under visible solar energy.

The Role of Strontium in CeNiO3 Nano-Crystalline Perovskites for Greenhouse Gas Mitigation to Produce Syngas.

The transition metal-based catalysts for the elimination of greenhouse gases via methane reforming using carbon dioxide are directly or indirectly associated with their distinguishing characteristics such as well-dispersed metal nanoparticles, a higher number of reducible species, suitable metal-support interaction, and high specific surface area. This work presents the insight into catalytic performance as well as catalyst stability of CexSr1-xNiO3 (x = 0.6-1) nanocrystalline perovskites for the production of hydrogen via methane reforming using carbon dioxide. Strontium incorporation enhances specific surface area, the number of reducible species, and nickel dispersion. The catalytic performance results show that CeNiO3 demonstrated higher initial CH4 (54.3%) and CO2 (64.8%) conversions, which dropped down to 13.1 and 19.2% (CH4 conversions) and 26.3 and 32.5% (CO2 conversions) for Ce0.8Sr0.2NiO3 and Ce0.6Sr0.4NiO3, respectively. This drop in catalytic conversions post strontium addition is concomitant with strontium carbonate covering nickel active sites. Moreover, from the durability results, it is obvious that CeNiO3 exhibited deactivation, whereas no deactivation was observed for Ce0.8Sr0.2NiO3 and Ce0.6Sr0.4NiO3. Carbon deposition during the reaction is mainly responsible for catalyst deactivation, and this is further established by characterizing spent catalysts.

Structure Engineering of Yolk-Shell Magnetic Mesoporous Silica Microspheres with Broccoli-Like Morphology for Efficient Catalysis and Enhanced Cellular Uptake.

Yolk-shell magnetic mesoporous microspheres exhibit potential applications in biomedicine, bioseparation, and catalysis. Most previous reports focus on establishing various interface assembly strategies to construct yolk-shell mesoporous structures, while little work has been done to control their surface topology and study their relevant applications. Herein, a unique kind of broccoli-like yolk-shell magnetic mesoporous silica (YS-BMM) microsphere is fabricated through a surfactant-free kinetic controlled interface assembly strategy. The obtained YS-BMM microspheres possess a well-defined structure consisting of a magnetic core, middle void, mesoporous silica shell with tunable surface roughness, large superparamagnetism (36.4 emu g-1 ), high specific surface area (174 m2 g-1 ), and large mesopores of 10.9 nm. Thanks to these merits and properties, the YS-BMM microspheres are demonstrated to be an ideal support for immobilization of ultrafine Pt nanoparticles (≈3.7 nm) and serve as superior nanocatalysts for hydrogenation of 4-nitrophenol with yield of over 90% and good magnetic recyclability. Furthermore, YS-BMM microspheres show excellent biocompatibility and can be easily phagocytosed by osteoclasts, revealing a potential candidate in sustained drug release in orthopedic disease therapy.

Discovery of a novel series of substituted quinolines acting as anticancer agents and selective EGFR blocker: Molecular docking study.

A Ta2O5-anchored-piperidine-4-carboxylic acid (PPCA) nanoparticle has been synthesized and characterized. It was then used as a highly effective nanocatalyst for the synthesis of quinolin-2(1H)-one derivatives through CO bond functionalization. The special advantage of this heterogeneous solid catalyst is the reusability of the catalyst for up to five cycles without any noticeable reduction in product yields. In comparison, healthy reaction profiles, wide substrate scope, excellent yields and easy workup conditions are the notable highlights of this approach. All the compounds were tested for their anticancer activity against MCF-7 (human breast), HepG2 (human liver), HCT116 (human colorectal), and PC-3 (human prostate) cancer cell lines with the MTT assay. All the compounds were shown to have moderate to good inhibitory effects on tested cancer cell lines. Besides, compounds 5b, 5c and 5d showed good selectivity against epidermal growth factor receptor-tyrosine kinase (EGFR-TK). Molecular docking results showed that active compounds showed a good affinity towards EGFR kinase (PDB ID: 6V6O) by forming two hydrogen bonds with Cys-797 and Tyr-801. All the compounds were screened for computational ADMET and Lipinski analysis.

Click synthesis of 1,2,3-triazole based imidazoles: Antitubercular evaluation, molecular docking and HSA binding studies.

Using Cu(I)-catalyzed cycloaddition of alkyne and azide reaction (CuAAC), a series of novel 1,2,3-triazole based imidazole derivatives (3a-e) have been synthesized. The synthesized molecules were characterized by spectroscopic techniques such as 1H NMR, 13C NMR, mass and elemental analysis. Antitubercular activity (anti-TB) against Mycobacterium tuberculosis H37Rv (Mtb) and cytotoxic activity against the mammalian Vero cell line was screened for the synthesized compounds. The compounds 3d and 3e displayed potent in vitro antitubercular activity and may serve as a lead for further optimization. Besides, the experimental findings were in line with the results of molecular docking. Also, the synthesized compounds have also been analyzed for ADME properties and the experimental finding facilitates the development of new and more potent anti-TB agents in this series in the future. Using fluorescence and UV-vis absorption spectroscopy, the binding interaction of compounds (3d and 3e) with human serum albumin (HSA) was investigated. The results showed that, as a result of HSA-compound complex, the fluorescence quenching of HSA by test compounds was a static quenching process. According to Forster's theory, energy transfer efficiency is calculated.

Structural investigations, quantum mechanical studies on proton and metal affinity and biological activity predictions of selpercatinib.

Cancer of the lungs and thyroid is particularly difficult to manage and treat. Notably, selpercatinib has recently been suggested as an effective drug to combat these diseases. The entire world is currently tackling the pandemic caused by the SARS-CoV-19 virus. Numerous pharmaceuticals have been evaluated for the management of the disease caused by SARS-CoV-19 (i.e., COVID-19). In this study, selpercatinib was proposed as a potential inhibitor of different SARS-CoV-19 proteins. Several intriguing effects of the molecule were found during the conducted computational investigations. Selpercatinib could effectively act as a proton sponge and exhibited high proton affinity in solution. Moreover, it was able to form complexes with metal ions in aqueous solutions. Specifically, the compound displayed high affinity towards zinc ions, which are important for the prevention of virus multiplication inside human cells. However, due to their charge, zinc ions are not able to pass the lipid bilayer and enter the cell. Thus, it was determined that selpercatinib could act as an ionophore, effectively transporting active zinc ions into cells. Furthermore, various quantum mechanical analyses, including energy studies, evaluation of the reactivity parameters, examination of the electron localisation and delocalisation properties, as well as assessment of the nonlinear optical (NLO) properties and information entropy, were conducted herein. The performed docking studies (docking scores -9.3169, -9.1002, -8.1853 and -8.1222 kcal mol-1) demonstrated that selpercatinib strongly bound with four isolated SARS-CoV-2 proteins.

Excited-state electronic properties, structural studies, noncovalent interactions, and inhibition of the novel severe acute respiratory syndrome coronavirus 2 proteins in Ripretinib by first-principle simulations.

Ripretinib is a recently developed drug for the treatment of adults with advanced gastrointestinal stromal tumors. This paper reports an attempt to study this molecule by electronic modeling and molecular mechanics to determine its composition and other specific chemical features via the density-functional theory (DFT), thereby affording sufficient information on the electronic properties and descriptors that can enable the estimation of its molecular bioactivity. We explored most of the physico-chemical properties of the molecule, as well as its stabilization, via the studies of the natural bond orbitals and noncovalent interactions. The electronic excitation, which is a time-dependent process, was examined by the time-dependent DFT with a CAM-B3LYP functional. The molecular docking study indicated that Ripretinib strongly docks with three known novel severe acute respiratory syndrome coronavirus 2 (SARS-n-CoV-2) proteins with a reasonably good docking score.

Au Nanoparticles Decorated Mesoporous SiO2 -WO3 Hybrid Materials with Improved Pore Connectivity for Ultratrace Ethanol Detection at Low Operating Temperature.

Semiconducting metal oxides-based gas sensors with the capability to detect trace gases at low operating temperatures are highly desired in applications such as wearable devices, trace pollutant detection, and exhaled breath analysis, but it still remains a great challenge to realize this goal. Herein, a multi-component co-assembly method in combination with pore engineering strategy is proposed. By using bi-functional (3-mercaptopropyl) trimethoxysilane (MPTMS) that can co-hydrolyze with transition metal salt and meanwhile coordinate with gold precursor during their co-assembly with PEO-b-PS copolymers, ordered mesoporous SiO2 -WO3 composites with highly dispersed Au nanoparticles of 5 nm (mesoporous SiO2 -WO3 /Au) are straightforward synthesized. This multi-component co-assembly process avoids the aggregation of Au nanoparticles and pore blocking in conventional post-loading method. Furthermore, through controlled etching treatment, a small portion of silica can be removed from the pore wall, resulting in mesoporous SiO2 -WO3 /Au with increased specific surface area (129 m2  g-1 ), significantly improved pore connectivity, and enlarged pore window (>4.3 nm). Thanks to the presence of well-confined Au nanoparticles and ε-WO3 , the mesoporous SiO2 -WO3 /Au based gas sensors exhibit excellent sensing performance toward ethanol with high sensitivity (Ra /Rg = 2-14 to 50-250 ppb) at low operating temperature (150 °C).

Synthesis of Novel Tetra(µ3-Methoxo) Bridged with [Cu(II)-O-Cd(II)] Double-Open-Cubane Cluster: XRD/HSA-Interactions, Spectral and Oxidizing Properties.

A new double-open-cubane core Cd(II)-O-Cu(II) bimetallic ligand mixed cluster of type [Cl2Cu4Cd2(NNO)6(NN)2(NO3)2].CH3CN was made available in EtOH/CH3CN solution. The 1-hydroxymethyl-3,5-dimethylpyrazole (NNOH) and 3,5-dimethylpyrazole (NNH) act as N,O-polydentate anion ligands in coordinating the Cu(II) and Cd(II) centers. The structure of the cluster in the solid state was proved by XRD study and confirmed in the liquid state by UV-vis analysis. The XRD result supported the construction of two octahedral and one square pyramid geometries types around the four Cu(II) centers and only octahedral geometry around Cd(II) two centers. Interestingly, NNOH ligand acts as a tetra-µ3-oxo and tri-µ2-oxo ligand; meanwhile, the N-N in NNH acts as classical bidentate anion/neutral ligands. The interactions in the lattice were detected experimentally by the XRD-packing result and computed via Hirschfeld surface analysis (HSA). The UV-vis., FT-IR and Energy Dispersive X-ray (EDX), supported the desired double-open cubane cluster composition. The oxidation potential of the desired cluster was evaluated using a 3,5-DTB-catechol 3,5-DTB-quinone as a catecholase model reaction.

Exo⇔Endo Isomerism, MEP/DFT, XRD/HSA-Interactions of 2,5-Dimethoxybenzaldehyde: Thermal, 1BNA-Docking, Optical, and TD-DFT Studies.

The exo⇔endo isomerization of 2,5-dimethoxybenzaldehyde was theoretically studied by density functional theory (DFT) to examine its favored conformers via sp2-sp2 single rotation. Both isomers were docked against 1BNA DNA to elucidate their binding ability, and the DFT-computed structural parameters results were matched with the X-ray diffraction (XRD) crystallographic parameters. XRD analysis showed that the exo-isomer was structurally favored and was also considered as the kinetically preferred isomer, while several hydrogen-bonding interactions detected in the crystal lattice by XRD were in good agreement with the Hirshfeld surface analysis calculations. The molecular electrostatic potential, Mulliken and natural population analysis charges, frontier molecular orbitals (HOMO/LUMO), and global reactivity descriptors quantum parameters were also determined at the B3LYP/6-311G(d,p) level of theory. The computed electronic calculations, i.e., TD-SCF/DFT, B3LYP-IR, NMR-DB, and GIAO-NMR, were compared to the experimental UV-Vis., optical energy gap, FTIR, and 1H-NMR, respectively. The thermal behavior of 2,5-dimethoxybenzaldehyde was also evaluated in an open atmosphere by a thermogravimetric-derivative thermogravimetric analysis, indicating its stability up to 95 °C.

High Reserve in δ-Tocopherol of Peganum harmala Seeds Oil and Antifungal Activity of Oil against Ten Plant Pathogenic Fungi.

This investigation included the chemical analysis of Peganum harmala (P. harmala) seed oil and its antifungal properties against 10 fungal species. Seed oils of six populations were analyzed using high performance liquid chromatography (HPLC) and gas chromatograph/mass spectrometry (GC-MS). The HPLC analysis indicated that P. harmala seed oil exhibited a very high level of tocopherol contents, with values in the range of 2385.66-2722.68 mg/100 g. The most abundant tocopherol isomer was δ-tocopherol (90.39%), followed by γ-tocopherol (8.08%) and α-tocopherol (1.14%). We discovered for the first time the presence of tocotrenols in P. harmala seed oils of the six populations studied. The GC-MS analyses revealed that linoleic acid was the main fatty acid (65.17%), followed by oleic acid (23.12%), palmitic acid (5.36%) and stearic acid (3.08%). We also studied the antifungal activity of seed oil of the Medenine (MD) population on ten fungal pathogens. The antifungal effects differed among pathogens and depended on oil concentrations. Seed oil of the MD population caused a significant decrease in mycelial growth of all fungi tested, with values ranging 31.50-82.11%, except for Alternaria sp., which showed no inhibition. The antifungal activity against the 10 selected fungi can be explained by the richness in tocols of the extracted oil and make P. harmala a promising crop for biological control. Furthermore, the importance of fatty acids and the wide geographic spread in Tunisia of this species make this crop a potential source of renewable energy.

Synthesis and Spectral Identification of Three Schiff Bases with a 2-(Piperazin-1-yl)-N-(thiophen-2-yl methylene)ethanamine Moiety Acting as Novel Pancreatic Lipase Inhibitors: Thermal, DFT, Antioxidant, Antibacterial, and Molecular Docking Investigations.

Three new tetradentate NNNS Schiff bases (L1-L3) derived from 2-(piperidin-4-yl)ethanamine were prepared in high yields. UV-Visible and FTIR spectroscopy were used to monitor the dehydration reaction between 2-(piperidin-4-yl)ethanamine and the corresponding aldehydes. Structures of the derived Schiff bases were deduced by 1H and 13C NMR, FTIR, UV-Vis, MS, EA, EDS, and TG-derived physical measurements. DFT/B3LYP theoretical calculations for optimization, TD-DFT, frequency, Molecular Electrostatic Potential (MEP), and highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) / were performed for L2. The in vitro antimicrobial activities of the three Schiff bases were evaluated against several types of bacteria by disk diffusion test using Gentamicin as the standard antibiotic. Schiff bases revealed good antioxidant activity by the DPPH method, and the IC50 values were compared to the Trolox standard. Pancreatic porcine lipase inhibition assay of the synthesized compounds revealed promising activity as compared to the Orlistat reference.

Adsorption of Azo Dye Methyl Orange from Aqueous Solutions Using Alkali-Activated Polypyrrole-Based Graphene Oxide.

The adsorption of methyl orange (MO) from aqueous solutions onto a KOH-activated polypyrrole-based adsorbent (PACK) was investigated using batch and fixed-bed column techniques. The structural, thermal, and morphological properties of the PACK, analyzed by various methods, support its applicability as an adsorbent. An adsorption kinetic study revealed a preferably pseudo-second-order (R2 = 0.9996) and rate-limiting step controlled by both film and intra-particle diffusions. The thermodynamic adsorption tests resulted in negative ΔG°, ΔH°, and ΔS° values, which decreased as the temperature and concentration increased, indicating the spontaneous and exothermic adsorption over 25-45 °C. The adsorption isotherms fit the experimental data in the order of Langmuir ≈ Freundlich > Temkin, with evidence of adsorption operating well via the monolayer physical adsorption process, and maximum monolayer adsorption ranging from 520.8 to 497.5 mg/g. The breakthrough curve of the fixed-bed column experiment was modeled using the Thomas, Yoon-Nelson, and Hill models, resulting in an equilibrium capacity of 57.21 mg/g. A 73% MO recovery was achieved, indicating the possibility of column regeneration. Compared to other adsorbents reported, PACK had comparable or even superior capacity toward MO. For cost-effectiveness, similar nitrogen-containing polymeric wastes could be exploited to obtain such excellent materials for various applications.

Efficient Zinc Vanadate Homojunction with Cadmium Nanostructures for Photocatalytic Water Splitting and Hydrogen Evolution.

Construction of a homojunction is an effective strategy for effective charge transfer to suppress charge carrier recombination in augmented photocatalysis. The present work reveals the synthesis of homojunction formation through the reinforcement of Cd nanostructures into a solid lattice of zinc vanadate (Zn3V2O8, ZnV) using the hydrothermal method. The formation of a homojunction between cadmium vanadate (CdV, Cd3V2O8) and ZnV was confirmed by various spectroscopic and electron microscopic techniques such as Fourier-transform infrared (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM) associated with energy-dispersive X-ray (EDX) mapping, transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and ultraviolet-visible spectrophotometry (UV-Vis). The synthesized material was explored for photocatalytic hydrogen (PC H2) production using the water splitting process under visible-light illumination. The spectroscopic and experimental results revealed that the formation of a CdV/ZnV homojunction significantly improved the transport of photogenerated charge carriers (electron-hole pairs) and thus resulted in enhanced H2 production efficiency (366.34 µmol g-1 h-1) as compared to pristine ZnV (229.09 µmol g-1 h-1) and CdV (274.91 µmol g-1 h-1) using methanol as a sacrificial reagent (SR) with water under visible-light illumination. The synergistic effect of Cd on ZnV NPs resulted in band gap reduction and broadened visible light absorption which was attributed to enhanced H2 production. The current study explains how a homojunction affects various features of important factors behind photocatalytic activity, which supports significant insights into the advancement of materials in the future.

Inhibiting Interfacial Nonradiative Recombination in Inverted Perovskite Solar Cells with a Multifunctional Molecule.

Interface-induced nonradiative recombination losses at the perovskite/electron transport layer (ETL) are an impediment to improving the efficiency and stability of inverted (p-i-n) perovskite solar cells (PSCs). Tridecafluorohexane-1-sulfonic acid potassium (TFHSP) is employed as a multifunctional dipole molecule to modify the perovskite surface. The solid coordination and hydrogen bonding efficiently passivate the surface defects, thereby reducing nonradiative recombination. The induced positive dipole layer between the perovskite and ETLs improves the energy band alignment, enhancing interface charge extraction. Additionally, the strong interaction between TFHSP and the perovskite stabilizes the perovskite surface, while the hydrophobic fluorinated moieties prevent the ingress of water and oxygen, enhancing the device stability. The resultant devices achieve a power conversion efficiency (PCE) of 24.6%. The unencapsulated devices retain 91% of their initial efficiency after 1000 h in air with 60% relative humidity, and 95% after 500 h under maximum power point (MPP) tracking at 35 °C. The utilization of multifunctional dipole molecules opens new avenues for high-performance and long-term stable perovskite devices.

Synthesis of Xanthan Gum Anchored α-Fe2O3 Bionanocomposite Material for Remediation of Pb (II) Contaminated Aquatic System.

Increases in community and industrial activities have led to disturbances of the environmental balance and the contamination of water systems through the introduction of organic and inorganic pollutants. Among the various inorganic pollutants, Pb (II) is one of the heavy metals possessing non-biodegradable and the most toxic characteristics towards human health and the environment. The present study is focussed on the synthesis of efficient and eco-friendly adsorbent material that can remove Pb (II) from wastewater. A green functional nanocomposite material based on the immobilization of α-Fe2O3 nanoparticles with xanthan gum (XG) biopolymer has been synthesized in this study to be applied as an adsorbent (XGFO) for sequestration of Pb (II). Spectroscopic techniques such as scanning electron microscopy with energy dispersive X-ray (SEM-EDX), Fourier transform infrared (FTIR), transmission electron microscopy (TEM), X-ray diffraction (XRD), ultraviolet visible (UV-Vis) and X-ray photoelectron spectroscopy (XPS) were adopted for characterizing the solid powder material. The synthesized material was found to be rich in key functional groups such as -COOH and -OH playing important roles in binding the adsorbate particles through ligand-to-metal charge transfer (LMCT). Based on the preliminary results, adsorption experiments were conducted, and the data obtained were applied to four different adsorption isotherm models, viz the Langmuir, Temkin, Freundlich and D-R models. Based on the high values of R2 and low values of χ2, the Langmuir isotherm model was found to be the best model for simulation of data for Pb (II) adsorption by XGFO. The value of maximum monolayer adsorption capacity (Qm) was found to be 117.45 mg g-1 at 303 K, 126.23 mg g-1 at 313 K, 145.12 mg g-1 at 323 K and 191.27 mg g-1 at 323 K. The kinetics of the adsorption process of Pb (II) by XGFO was best defined by the pseudo-second-order model. The thermodynamic aspect of the reaction suggested that the reaction is endothermic and spontaneous. The outcomes proved that XGFO can be utilized as an efficient adsorbent material for the treatment of contaminated wastewater.

Efficient light-driven hydrogen evolution and azo dye degradation over the GdVO4@g-C3N4 heterostructure.

A straightforward hydrothermal technique was used for the synthesis of a g-C3N4/GdVO4 (CN/GdV) heterostructure as an alternate material for energy and environmental applications. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS) were used to characterize the synthesized g-C3N4 (CN), GdVO4 (GdV), and the CN/GdV heterostructure. The characterization results revealed the distribution of GdV over CN sheets. The as-fabricated materials were tested for their capacity to evolve hydrogen gas and degrade two azo dyes (Amaranth; AMR and Reactive Red2; RR2) in the presence of visible light. When compared to pure CN and GdV, the efficiency of CN/GdV toward hydrogen evolution was high, with H2 evolution of 8234, 10 838, and 16 234 µmol g-1 in 4 h, respectively. The CN/GdV heterostructure was able to degrade 96% and 93% of AMR (60 min) and RR2 (80 min), respectively. The enhanced activity with CN/GdV could be attributed to the type-II heterostructure and decreased recombination of charge carriers. The intermediate analysis of AMR and RR2 degradation was conducted using mass spectrometry (MS). The mechanism of photocatalysis was investigated and is discussed based on the optical and electrochemical characterizations. The efficient photocatalytic characteristics of CN/GdV could promote further research on metal vanadate nanocomposite materials.

Hydrothermal Synthesis of a Magnesium Vanadate-Functionalized Reduced Graphene Oxide Nanocomposite for an Efficient Photocatalytic Hydrogen Production.

Herein, we reported the fabrication of a magnesium vanadate-reduced graphene oxide (Mg3V2O8-rGO) composite. Further, the structural morphology of the as-prepared Mg3V2O8-rGO composite was studied by scanning electron microscopy. Powder X-ray diffraction and energy-dispersive X-ray spectroscopy techniques were also adopted to check the phase purity and elemental composition of the prepared Mg3V2O8-rGO composite. Mg3V2O8-rGO possesses a band gap of 2.98 eV, which prompted us to explore its photocatalytic activity for hydrogen (H2) evolution reaction. The Mg3V2O8-rGO composite demonstrated the generation of a reasonable amount of H2 evolution (97.45 µmol g-1), which is relatively higher than that of pristine Mg3V2O8 (17.45 µmol g-1). This may be attributed to the presence of synergism between Mg3V2O8 and rGO. In addition, Mg3V2O8-rGO also showed good stability and suggested its potential application for photocatalytic H2 evolution applications. So far, no report is available on the use of Mg3V2O8-rGO as a photocatalyst for H2 evolution. We propose the potential role of the Mg3V2O8-rGO composite for photocatalytic H2 evolution applications.

Fluorometric Sensing and Detection of p-Nitroaniline by Mixed Metal (Zn, Ni) Tungstate Nanocomposite.

Aromatic amines are important chemical intermediates that hold an irreplaceable significance for synthesizing many chemical products. However, they may react with substances excreted from human bodies to generate blood poisoning, skin eczema, and dermatitis disease and even induce cancer-causing high risks to human health and the environment. Metal tungstates have been proven to be highly efficient materials for developing various toxic gases or chemical detection sensor systems. However, the major factors of the sensors, such as sensitivity, selectivity, stability, response, and recovery times, still need to be optimized for practical technological applications. In this work, Ni-doped ZnWO4 mixed metal tungstate nanocomposite material was synthesized by the hydrothermal method and explored as a sensor for the fluorometric determination of p-nitroaniline (p-NA). Transmission electron microscopy (TEM) was used for the elucidation of the optimized particle diameter. Scanning electron microscopy (SEM) was employed to observe the surface morphological changes in the material during the solid-state reactions. The vibration modes of as-prepared samples were analyzed using Fourier-transform infrared spectroscopy (FTIR). The chemical bonding and oxidation states of individual elements involved in material synthesis were observed using X-ray photoelectron spectroscopy (XPS). The PL activities of the metal tungstate nanoparticles were investigated for the sensing of p-nitroaniline (p-NA). The obtained results demonstrated that ZnNiWO4 was more effective in sensing p-NA than the other precursors were by using the quenching effect. The material showed remarkably high sensitivity towards p-NA in a concentration range of 25-1000 µM, and the limit of detection (LOD) value was found to be 1.93 × 10-8 M for ZnWO4, 2.17 × 10-8 M for NiWO4, and 2.98 × 10-8 M for ZnNiWO4, respectively.